The present invention relates to a toy vehicle system for simultaneously but individually controlling two or more electrically operated toy vehicles. In particular, the toy vehicles are in the form of electric model trains in which a single circuit is comprising a common track therefor used to control the vehicle direction independently of the vehicle velocity.
A system known in the art for controlling several trains of the above species provides several circuits so that each train is associated with one circuit. Thus a control arrangement for three trains may be realized by the use of an overhead line and a center rail. This center rail serves as the ground or common return conductor, for example, while each of the track rails as well as the overhead line cooperate with the center rail to provide three separate circuits for the three trains. The disadvantage of this system is that it is not possible to rebuild an arrangement which was not originally designed to be used for controlling several trains. This results from the condition that entirely new tracks and additional overhead lines must be installed for such trains which were originally built without the intent for controlling several trains at the same time. It is also a disadvantage of the conventional systems that the number of trains which may be independently controlled is limited.
An arrangement is also known in the art which adapts single-train control to controlling several trains by applying a regulated constant voltage (AC or DC) to both rails. A separate HF AC voltage is superimposed on the constant voltage for each locomotive which is to be controlled. Each locomotive has, in turn, a HF tuned receiver which enables the locomotive selectively to be controlled. Frequency control thus is used for the purpose of switching the trains between forward and reverse drives. Further control for the locomotives is determined by the amount of current taken from the rail circuit to which constant voltage is supplied for driving the locomotives. The actual energy for driving several trains is derived from the constant voltage applied to each train by the rail circuit.
The preceding conventional arrangement has the same disadvantage as the known arrangements based on half-wave control which is adapted only for two train operation. This disadvantage resides in the requirement that several or all locomotives must be supplied with corresponding control installations for operating their electrical motors. Thus, it is not possible, to convert a common single-train toy arrangement to one which consists of electronically controlled trains, through the use of simple means.
Accordingly, it is an object of the present invention to overcome the disadvantages of such known prior art arrangements and provide a toy vehicle arrangement for individually and simultaneously controlling two or more electrically operated toy vehicles on a common track.
It is a particular object of the present invention to provide a toy vehicle arrangement for electrical model trains which are controlled by a single circuit so that the vehicle direction is independent of the vehicle velocity.
Another object of the present invention is to provide a toy vehicle arrangement of the foregoing character in which extensive rebuilding of single-train arrangements is not essential for adaptation to multiple-train operation.
The objects of the present invention are achieved by providing that the first toy vehicle is driven in the conventional manner by AC current, DC current, or rectified AC current. The velocity of such first toy vehicle is controlled by varying the voltage amplitude, whereas the vehicle direction is controlled by switching the polarity. The vehicle direction of such first toy vehicle may also be determined by applying a relatively high voltage to the applied driving circuit. Each additional toy vehicle receives its driving energy as well as the control information for direction and velocity in the form of a supply voltage consisting of an AC component superimposed upon the supply voltage for the first toy vehicle. The frequency of this AC component is substantially greater (2X, for example) than the frequency (60H, for example) of the utility line outlet supply. It is to be understood thereby that each additional toy vehicle is to be associated with a different frequency of the superimposed AC component.
In the following description, the expression "supply voltage" is to denote the supply voltage used to drive the first toy vehicle. The expression "AC supply voltage" is to denote a low frequency AC voltage used for driving an additional toy vehicle. The frequency of this AC supply, however is substantially higher than the frequency (25-60H) of the utility line outlet supply voltage.
The essential difference between the toy vehicle arrangement of the present invention and conventional arrangements for multiple train control resides in the feature that the different AC supply voltages for the additional toy vehicles is not used as previously for selective control of additional toy vehicles which derive all of their driving energy from a common track circuit. Instead, the AC supply voltage in accordance with the present invention, supply simultaneously the energy carrier for actually driving the additional toy vehicles. Through this arrangement, it is possible to obtain a multiple-train control from an original single-train unit, in which a regulated constant supply voltage is not suitable for the track circuit itself, since voltage amplitude variation for controlling the first toy vehicle is necessary.
In a further embodiment of the present invention, the velocity of the second vehicle, as well as any additional vehicles, can be controlled by the amplitude of the associated low-frequency basis supply voltage. The vehicle direction can be controlled by the waveform.
For this purpose, each AC supply voltage for an additional toy vehicle may be made advantageously in the form of nonsymmetrical half-waves having a time-average value of substantially zero. In this manner the polarity of the difference voltage of both maximum values can serve for determining the direction of the vehicle. This difference voltage may be obtained in a simple manner by the application of a voltage multiplying circuit with an ohmic voltage divider.
Since the force required to start a toy vehicle is generally substantially greater than the force needed to maintain a uniform velocity, a substantially higher voltage is required by the motor when starting up in comparison with the voltage required for cruising. As a result of this, the toy vehicle as, for example a model train, starts up abruptly from its stationary position and drives with substantially relatively high velocity. This resultant velocity may not be diminished substantially by moving back the operating regulator, since this causes dropping below a predetermined threshold level for stopping the train, whereby the train is immediately stopped in place when this threshold level is not exceeded.
A substantial improvement in the low-speed operating characteristics in the arrangement is achieved, in accordance with the present invention, by providing that the AC supply voltage for the additional toy vehicles has a number of oscillating pulses with relatively low pulse repetition frequency. With this arrangement, a sufficiently large voltage is made available for accelerating purposes and for overcoming frictional resistance. At the same time, the duration of the latter voltage is substantially short and applies, thereby, only an impulse to the toy vehicle. By applying a predetermined pulse repetition frequency as, for example, the frequency which corresponds to that of the utility line outlet supply, a reliable slow start-up of the toy vehicle may be obtained. This is particularly desirable in model trains. For this purpose, it is also possible to make the pulse repetition frequency equal to twice the frequency of the utility line outlet supply.
The use of the pulse drive described above at full speed may lead to undesirably high voltage pulses in the motor, and this may result in poor motor operation as well as a disturbed and noisy fast-driving operation. These undesirable characteristics can be avoided, in accordance with the present invention, by providing that when the amplitude of the AC supply voltage increases, the pulse width also increase at substantially fixed pulse repetition frequency. In this manner, there is always a transition from start-up to a steady-state voltage for full speed when using the preceding pulse driving arrangement.
The frequencies of the AC supply voltages can generally be determined through applied pulse generators or oscillators. The pulse repetition frequency, however, can be obtained in an advantageous manner from the utility line outlet supply frequency. Thus, the pulse repetition frequency may be equal to the utility frequency or to a multiple of this line frequency.
A particularly simple construction, in accordance with the present invention, is obtained when the control console of each additional toy vehicle is connected in series with the line between the control console of the first vehicle and the rail circuit. With this arrangement, the AC supply voltage is superimposed upon the first supply voltage, and all control consoles have a common utility line outlet. Thus, the current supply lines for the first control console are passed through all additional control consoles.
It is also within the framework of the present invention that the AC supply voltages include additional information for actuating mechanical or electrical auxiliary equipment on the toy vehicles. By way of example such information may be directed for the purpose of switching lights on and off, for actuating remote-controlling couplings, or for controlling a crane installation.
The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and to its method of operation together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.